Thread View: comp.sys.masscomp
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Started by dale chayes
Tue, 14 Mar 1989 17:43
ieee copysign() in the sun world
Author: dale chayes
Date: Tue, 14 Mar 1989 17:43
Date: Tue, 14 Mar 1989 17:43
36 lines
1857 bytes
1857 bytes
While porting some in-house code, I have come across a funtion in the math.h include file called copysign(x,y) which returns x with the sign of y. While this seems trivial, I wondered if it is significant? The comments in Sun's include file say that these functions are reccomended by IEEE, and sure enough they are. As a matter of fact, copysign() is the first funtion in the appendix of ANSI/IEEE Std 754-1985 "Recommended Functions and Predicates." The text (in the appendix) says: Copysign()x,y) returns x with the sign of y. Hence, abs(x)=copysign(x,1.0), even it (sic) x is NaN. It turns out, that there are a whole list of "recommended" funtcions in the predicate that don't appear to be supplied by Concurrent/Masscomp. I'm mostly a hardware guy (especially when it comes to this kind of stuff.) Anyone got any clues? Dale ------------------------------------------------------------------------ -- Dale Chayes Lamont-Doherty Geological Observatory of Columbia University Route 9W, Palisades, N.Y. 10964 dale@lamont.ldgo.columbia.edu voice: (914) 359-2900 extension 434 fax: (914) 359-6817 The MASSCOMP USERS' SOCIETY newsgroup is comp.sys.masscomp. Articles to: masscomp@soma.bcm.tmc.edu or uunet!soma.bcm.tmc.edu!masscomp Administrative stuff: masscomp-request@soma.bcm.tmc.edu Stan Barber, Moderator
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